Search

This paper proposes a control and monitor of single-stage single-phase T-type grid-connected inverter based on IoT. The MPPT (maximum power point tracking) algorithm, modulation method of single-phase T-type, the PR (proportional-resonant) current controller, and SOGI PLL algorithm are presented in this paper. With H-bridge, the level of inverter voltage is 3, the low level is the cause of the appearance of harmonic components and power loss in the grid- connected solar application. To overcome this problem, this paper adopts a T-type single-phase with 5 voltage levels. The presented inverter has a half-bridge switching leg and a T-type switching leg. Besides, the grid-connected energy can be easily supervised during DSP processing via the ESP32 wi-fi module by the UART interface. A prototype and mobile app are built for performance verification, which can test single-phase T-type topology. Simulation and experimental results are presented to verify the effectiveness of the proposed strategy.

This paper presents the implementation of a two-stage light-emitting diode (LED) driver based on commercial integrated circuits (IC). The presented LED driver circuit topology, which is designed to drive a 150 W LED module, consists of two stages: AC-DC power factor correction (PFC) stage and DC/DC power converter stage. The implementation of the PFC stage uses IC NCP1608, which uses the critical conduction mode to guarantee a unity input power factor with a wide range of input voltages. The DC/DC power converter with soft-switching characteristics for the entire load range uses IC FLS2100XS. Furthermore, the design of an electromagnetic interference (EMI) filter for the LED driver and the dimming control circuit are discussed in detail. The hardware prototype, an LED lighting system, with a rated power of 150 W/32 V from a nominal 220 V/50 Hz AC voltage supply was tested to show the effectiveness of the design. The presented LED driver was tested for street lighting, and the experimental results show that the power factor (PF) was higher than 0.97, the total harmonics distortion (THD) was lower than 7%, and the efficiency was 91.7% at full load. The results prove that the performance of the presented LED driver complies with the standards: IEC61000-3-2 and CIRSP 15:2009.

This paper concerned with the development and implementation of smart street lighting control system based using Led lamp and Lora Wireless communication. Currently, a traditional street lights are automatically turn on or off based on timer or day/night sensor. Recently, the conventional light sources are replaced by Led, which have so many advantages such as: energy savings, long lifetime, high reliability, pure light color, fast response, and friendliness to the environment. Furthermore, the intensity of the LED can be controlled easily. In this paper, the smart lighting system is designed to control and monitor devices via wireless transmission frequencies below 1 GHz. The smart lighting system has been built at Hochiminh City University of Technology to meet the standards for data transmission.

Currently, oil pollution at sea is one of the serious marine pollution issues that are of great concern to the international community. The incidents of oil exploitation and transportation in the world have become a great threat to the environment in general and ecosystems in particular. Many oil spills have occurred with serious long-term consequences for the ecological environment. Oil pollution in the East Sea in general and oil pollution in the Vietnam Sea in particular are not out of that situation. Marine ecosystems are one of the most important resources for Vietnam's development. However, in recent years, the marine ecosystem has been subject to many negative impacts from the environment, especially the risk of pollution caused by the oil spill when Vietnam is a country with large oil exploitation and import and export activities. In fact, evaluation methods have been widely applied to accurately identify losses. These losses will be an important basis to make decisions to sanction pollution acts. It is also the forecast information channel for ministries and agencies in development planning and devising strategies to minimize losses from the oil spill.

Zr-doped titania of anatase structure type has been prepared by a combined sol–gel and chemical vapour deposition (CVD) process. The material has been characterized by XRD, TEM and chemical analysis. The photocatalytic performance has been investigated in the oxidative decomposition of the pharmaceutical ibuprofen (IBP) down to low ppm concentrations. The change of the composition of the reaction solution after photocatalytic treatment was followed by UV–Vis spectroscopy and GC/MS. Formation of reaction intermediates was studied by HPLC coupled electrospray ionization time-of-flight mass spectrometry ESI-TOF-MS. The catalytic performance has been studied by varying the catalyst and substrate concentration as well as changing the catalyst-to-substrate ratio. The influence of pH, adsorption and re-use of the catalyst has been tested. The results confirm the high catalytic activity of Zr-doped titania compared to pure titania at low catalyst loading. The material shows the improved textural mesoporosity. However, more reaction intermediates were formed, leading to faster deactivation of the photocatalyst. ESI-TOF-MS measurements point to the formation of a couple of reaction intermediates, which poison the catalyst.